Around 2:30 pm, subcontractors were creating an opening using a blowtorch on the mobile roof of a 10,000-m³ gasoline tank for the purpose of installing a gauge. The heat ignited vapours within the tank, which then exploded killing all 3 subcontracted employees.

An investigation revealed that the subcontractor had received from the site operator an authorisation to work in a confined space as well as a hot work permit. Moreover, gas measurements were recorded at 7 am. Yet nothing indicated that gas detection was repeated upon returning from lunch or before resuming the job.